Transcript for John Brennan Faces His Critics at CIA Nomination Hearing

And today in washington, the man at the very center of america's secret war on terrorism appeared in front of the cameras. Defending the use of drones and their controversial target. John brennan answered his critics today and abc's chief white house correspondent jonathan karl was there. I'm honored to appear before you today -- Reporter: Even before he could introduce himself, the president's choice to run the cia was repeatedly interrupted by anti-war protesters. Please remove. Reporter: It was a rare public appearance for a man who works in a windowless basement office of the white house. An architect of the president's war on terror, especially the rapid expansion of the drone strikes. It's largely been a secret war, but brennan promised to at least tell congress every time the cia targets and kills suspected terrorists. If I were to go to cia and the cia was involve in any type of lethal activity, I would damn well make sure this committee had that information. Absolutely. Reporter: Brennan refused to confirm that the u.S. Was being hind the 2011 strike that killed an american citizen al qaeda leader anwar al awlaki, born in new mexico. But he forcefully defended making him a target. He was intimately involved in activities that were designed to kill innocent men, women and children and mostly americans. He was determined to do that. Reporter: Critics say the administration has relied so heavily on targeted killings that they don't even try to capture terrorists anymore. Brennan said that's not true. There's not been an occasion that I'm aware of where we had the opportunity to capture a terrorist and we didn't. Reporter: The drone strikes have come under intense criticism for killing innocent bystanders, something the u.S. Has never specifically acknowled acknowledged. I believe we need to acknowledge it. We need to acknowledge it publicly. Reporter: Brennan isn't done yet. He still faces a closed door classified hearing next week on the cia's most secret programs. Jonathan karl, abc news, the white house.

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